The purpose of the proposed study is to determine lymph pressure in the villi of small intestine of rats, or other mammals during fluid transport under various pathophysiological conditions such as in hemorrhagic shock, intestinal obstruction, at elevated venous pressure and so forth. The change of tissue fluid pressure or capillary filtration under these conditions can be inferred from the change of lymph pressure. The lymph pressure is determined under various circumstances in an attempt to elucidate the role of the lymphatic system in fluid transport from the intestine.